I have been trying to sort out my 86 245's problems since October now.

Here is the series of events that have taken place since then:


-Installed a new wiring harness (ebay bought)

=The car ran rough, would die, etc. Acted like it had a bad AMM or O2 or temp sensor.

-Installed a new temp sensor. Problems remained the same.

-Installed a new o2 sensor. Problems remained the same.

At this point I started to do some checking per Bentley manual.

My AMM tested OK. But, when you pull the AMM harness, the car starts and idles perfectly and runs fine. (you can't drive it though)

-Got a new ECU and installed. Problem remains the same.

-Got another AMM and put it in. PROBLEM remains the same.


- - -

The only thing I can think is that the wiring harness is bad. I'm curious of some tests I can do on it. The harness was perfect looking when I installed it.

But what could be the problem.

Symtoms are (with the AMM hooked up) hard starting.. Idles up quickly and dies. If you nurse the fuel pedal for 5 minutes, you can get it to idle roughly and drive it, but power REALLY lacks. Runs super lean too.

HELP :)

Thanks,

Luke.

so far, I have 2 ECUs, 2 AMMs, 2 temp sensors, and one ripped up rotted harness, and one potentially non-working one.

There are so many problems that can lead to these symptoms that it's sometimes hard to find a good starting point. I'd check to make sure your AMM and temperature sensor (not the sender, it doesn't send info the ECU) are getting a good connection. If they're poorly connected, they'll cause problems. I'd also check to be sure you don't have any leaks in the air intake system. Be sure all hoses are connected and not cracked. A leak will cause starting, revving, then dying like you mentioned. As far as the running lean goes, I don't really know. Usually if something breaks Volvos like to run rich. Where did you buy the AMM? If it was rebuilt it won't be nearly as reliable as even a used Volvo original. I'd also check the ignition timing to be sure it isn't way off for some reason. Finally, try shutting the idle air control motor (underneath intake manifold, regulates idle) as per the manual's instructions and adjusting the airflow via the screw on the throttle body to see if you can get a positive result. This could help as well.

There's a lot of stuff to check. Hopefully this'll help you find the problem. Good luck.
--
Isaac Babcock - '83 245DL 'Borkie' and '83 244 turbo project

what symptoms did you have before changing the harness?
If you didnt have any of the symptoms that you have now, logic points to the harness as the fault.

Can you do continuity checks on the amm wiring circuits? Maybe the producer of the harness didnt get it quite right.

I would try to, using the diagrams, sort it out enough to do some continuity checks. Make sure the harness is routed properly.

Did you do voltage and continuity checks?

Luck

I didn't do any of those checks yet, because I don't have any voltages.

I'm curious if anyone has the service manuals with some test voltages the harness is supposed to supply to the AMM.

or resistances, etc.

(I will try to recheck the Bentley manual for some info)

Thanks for any help.

This problem occured after I installed the harness.

Something weird though: The car is a 5 speed manual, but the orange, overdrive-off light on the cluster is always lit now.

Right before I changed the harness over, this light came on, and I thought changing the harness woudl remedy the problem, but it did not.

So that has always been a curiosity of mine. Why does that lamp come on, etc.